Molecular breast imaging found more tumors in women with dense breasts

ASCO Breast Cancer Symposium

The results of a study conducted at the Mayo Clinic showed molecular breast imaging to be a more effective cancer screen for women with dense breasts.

Carrie B. Hruska, PhD, a research fellow in the department of radiology at the Mayo Clinic in Rochester, Minn., discussed the results during an online press conference yesterday.

The researchers screened 940 women with both molecular breast imaging and mammography; 375 of those patients have completed a 15-month follow up. The patients had all been deemed as high-risk for breast cancer and all had a breast density >50%.

The investigators found a total of 13 tumors in 12 patients. Hruska said molecular breast imaging discovered 10 tumors and mammography discovered three. Using the two techniques together would have discovered 11 total tumors, she said.

Molecular breast imaging was more sensitive than mammography (75% vs. 25%) and more specific (93% vs. 91%), but Hruska said the new technology should not replace the standard screen.

“We believe (molecular breast imaging) has a role in finding cancers that are occult in mammography,” she said. “We’re certainly not advocating replacing mammography in any way. We think it would have a role as an additional test for women who aren’t served as well as we’d hope by mammography.”

An estimated 25% of women aged 40 years and older have dense breast patterns, and 10% to 15% of tumors are invisible to mammography, according to Hruska.

She said the eventual goal is to introduce molecular breast imaging as a lower-cost alternative to MRI. She estimated the screen would cost roughly the same as mammography and ultrasound, and about one-quarter as much as MRI.

Hruska said researchers are conducting a retrospective study comparing molecular breast imaging with MRI. She said that, so far, they have found 98% concordance between the two tests, and added that a prospective study began this month.

“We hope over the next year to launch it as more of a clinically available unit,” she said. “There’s a lot of work that needs to be done to identify its role in a clinical setting.”

Hruska will present this data at the ASCO Breast Cancer Symposium on Sunday. – by Jason Harris

One of the subtle aspects of this preliminary study is that it looked at a targeted group of women — women who had an increased risk as defined by a family history or by dense breasts. One of the changes we may see in the years ahead are strategies for breast cancer screening that are more individualized. We talk about personalized medicine when we talk about breast cancer treatment, but more and more, we may be getting away from one size fits all in terms of screening approaches, and instead think about screening approaches that are directed more to an individual woman based both on her risk and on the characteristics of her breasts.

– Eric Winer, MD

Director of the Breast Oncology Center at Dana-Farber Cancer Institute